More than one kind of image-generating system for sampling target object is able to be implemented in clinical, so that doctor can acquire multiple models of medical images, such as Computed Tomography (CT), Magnetic Resonance (MR) or ultrasound image. The principle of ultrasound image fusion navigation is, through space positioning devices (usually Magnetic locating sensor fixed on a probe), to built a spatial corresponding relation to real-time ultrasound images with other pre-acquired modality data (such as CT or MR image) and display the overlapped cutting sections images with the pre-acquired modality data for achieving the fusion of above two kinds of images. Under above, these two kinds of images are used both in diagnosis process and treatment process to combine the high resolutions feature of CT or MR with the real-time feature of ultrasound image so as to provide more detail diagnosis information for doctor in clinical to increase the effect of treatment.
In the ultrasound image fusion navigation system, the most important technique point is to register ultrasound images with the modality data. In detail, the practice of above registering point is to map the position of the point (or plane) of the ultrasound images in a world coordinate system with the position of the point (or plane) of the modality image in a world coordinate system correspondingly. Acquiring target position in the world coordinate system precisely is in significant effect for increasing the accuracy of registration.
The conventional registration technique is based on real-time ultrasound detection; doctor acquires ultrasound images for providing registering information by freezing the present frame. This kind of method, processing the real-time ultrasound image frame by frame, is well known for those skilled in the art. In addition, if doctor wants to acquire certain section image in certain breath depth, patient usually is asked to cooperate by precisely controlling his breath. Especially, when image fusion of abdominal organs for those patients, who's breath way is in abdominal breath way, is conducted, huge errors is generated because of the movement, rotation and deformation caused by the abdominal breath of patient. Therefore, patient is asked to precisely controlling his breath. It raises the requirements for both doctor and patient. If patient cannot control his breath well enough or doctor has a lack of experience, the effect is usually not satisfied so as to reduce the accuracy of registration and the successes rate for image fusion. Right now, the method for eliminating breath effect is depending on doctor's decisions by manually determining breath phase or adding a sample sensor for sample breath control. However, the performances of above solutions are all poor and unsatisfied.